A firm evidence base has emerged supporting screening and brief intervention for alcohol use in healthcare settings. However, important gaps exist in the evidence for screening and brief intervention for illegal drug use. Rigorous research is needed that tests the effectiveness of screening and brief intervention for illegal drug use. In the proposed project, Friends Research Institute is partnering with Sangre de Cristo Community Health Partnership, the organization responsible for implementing the SAMHSA Screening, Brief Intervention, Referral, and Treatment (SBIRT) Initiative at over 35 primary care sites throughout the State of New Mexico since 2003. The proposed study will use a randomized controlled trial to compare the effectiveness of a standardized interpersonal brief intervention (IBI) based on motivational interviewing (currently used in the New Mexico SBIRT initiative) with a promising computerized brief intervention (CBI) in reducing illegal drug use and its associated health consequences. In addition, the study will assess whether patients' computer experience differentially moderates the effectiveness of the two interventions. The study will take place at two large primary care clinics in New Mexico. All patients will complete a screening for substance use via the Alcohol, Tobacco, and Substance Involvement Screening Tool (ASSIST) as part of regular clinical care. Patients who score in a moderate-risk category for illegal drug use (n = 360, 180 at each site) will be randomized within their respective clinics to the IBI or CBI condition. Patients with high-risk drug use will be referred for more intensive services as per standard clinical practice. Primary outcomes include drug use levels for major substances of abuse as measured by radio immunoassay analysis of hair samples, as well as global illicit drug risk ASSIST scores. Secondary outcomes include self-reported frequency of hospitalizations, emergency room utilization, injuries, psychological distress, HIV risk behaviors, arrests, missed work days, and earned income. Data analysis will be conducted using a Generalized Linear Mixed Model approach. An effective computerized brief intervention has the potential to make a substantial impact on SBIRT practice and improve public health. An effective CBI has the potential to offer a more acceptable format for addressing drug use behaviors than an interpersonal encounter, and has the expected advantages of having high reach and easy replication with comparatively lower investment of clinicians' time and resources. PUBLIC HEALTH RELEVANCE: The relevance of this research to public health will show that targeted screening in primary care health settings for moderate drug use will have a significant impact on public health by implementing brief interventions that target risky behaviors in moderate drug using individuals. This research, which also tests the differential effectiveness of two brief interventions for illegal drug use, has the potential to make a significant contribution to understanding the role that brief interventions have in reducing drug use and its associated consequences.